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Roots & Shoots Blog

Increasing photosynthetic efficiency to maximize crop yield

Tuesday, 28 March 2017

Roots & Shoots’ March Guest blogger: Hui Jiang is a Senior Research Associate in Dr. Tom Brutnell’s lab, Enterprise Rent-A-Car Institute for Renewable Fuels at the Danforth Center. Hui’s research focuses on using forward genetics to identify and characterize genes that are involved in C4 photosynthesis and biomass production in Setaria viridis, and translate the information into related important crops such as maize and sorghum to increase photosynthesis efficiency and maximize crop yield.

I grew up in the capital city of Shanxi province, located in the northern region of China. Whenever I traveled to the countryside and saw the golden fields of wheat, millet and rice, I would always stare in fascination and contemplation: fascinated by how much food was produced and contemplating how to increase the harvest. I dreamed of becoming a plant scientist and doing research to increase crop yield.

After graduating from college with a Bachelor’s degree in Plant Physiology, I worked at the Chengdu Institute of Biology for more than ten years. Our research goal was to develop new crop materials and varieties through genetic engineering. We primarily focused on rice. During that period, I gradually came to realize the importance of combining traditional breeding methods with modern biotechnology. I made up my mind to dedicate my career to crop improvement.

My dream started to come true when I joined Cornell University. In 2001, I joined Dr. Ray Wu’s lab at Cornell as a visiting fellow, supported by a scholarship from the Chinese Academy of Sciences. I was involved in a project on the functional genomics of rice and my work was focused on the optimization of Agrobacteium-mediated rice transformation. Three years later I became a graduate student in the Department of Plant Breeding and Genetics at Cornell under the guidance of Dr. Susan McCouch, working on the fine mapping and evolutionary history of the rice gene GS3 that confers grain size.

Panicle phenotypes of NMU mutants. Bar length: 1cm.

After graduation, I went to a lecture that Dr. Tom Brutnell gave graduate students about his lab’s pioneering work using Setaria viridis as an emerging model system for C4 grasses. He talked about how Setaria is unique model compared to other model grasses such as rice because it utilizes the highly efficient C4 photosynthesis and has many desirable features including small stature and short life cycle. The identification and characterization of genes of interest in Setaria can be translated to closely related important crops such as maize and sorghum. As soon as the lecture ended, Dr. Brutnell asked a question that became a turning point in my life: Would any of you like to work on Setaria? Although I didn’t say anything out loud at the time, the answer in my head was a resounding yes. I grew up eating xiao mi or foxtail millet (a domesticated cousin of wild green foxtail millet) as our staple food. I have always enjoyed the nutritious value and delicious taste of xiao mi for so many years, but I had never imagined that the crop I grew up eating could later become a promising genetic model for C4 grasses. Setaria was fascinating and it showed incredible potential, and I knew right then and there that I wanted to be a part of its future.

Shortly after that, I emailed Dr. Brutnell and asked if I could work on Setaria viridis in his lab. He replied to me immediately and I became a member of the Brutnell lab a few months later, working on this promising new model species.

Our lab has also developed a chemically induced mutant population (consisting ~20,000 mutant families) and we’ve screened approximately 3,000 mutant families. Many interesting mutant phenotypes have been observed (Adapted from Jiang et al., 2017). Currently, we are using Bulked Segregant Analysis (BSA) followed by deep sequencing to map genes underlying agronomically important traits. In the future, we hope to use forward genetics to identify genes associated with C4 photosynthesis and biomass production in Setaria viridis and then translate the information into closely related crops such as maize and sorghum. Our ultimate goal is to increase photosynthesis efficiency and maximize crop yield.